Recently, the 3rd generation partnership project (3GPP) has approved the “Study on New Radio Access Technology”, which is a study item for research on next-generation/5G radio access technology. On the basis of the Study on New Radio Access Technology, Radio Access Network Working Group 1 (RAN WG1) has been discussing frame structures, channel coding and modulation, waveforms, multiple access methods, and the like for a new radio (NR). It is required to design the NR not only to provide an improved data transmission rate as compared with the long term evolution (LTE), but also to meet various requirements in detailed and specific usage scenarios.
An enhanced mobile broadband (eMBB), a massive machine-type communication (mMTC), and an ultra-reliable and low latency communication (URLLC) are proposed as representative usage scenarios of the NR. In order to meet the requirements of the individual scenarios, it is required to design NR to have flexible frame structures, compared with the LTE.
On the other hand, in orthogonal frequency-division multiplexing (OFDM)-based wireless communication systems, a cyclic prefix is included in the front of an OFDM symbol in order to cope with multi-path delay spread. In the case of the LTE/LTE-Advanced system, the cyclic prefix is included in front of each OFDM symbol.
Specifically, in the LTE/LTE-Advanced system, a base station configures i) OFDM based resource elements with the same subcarrier spacing and symbol duration and ii) the cyclic prefix according to a cell size and a delay spread characteristic by. Then, a user equipment performs detection of the length of the cyclic prefix configured in any cell through a process of adjusting time/frequency synchronization for the corresponding cell after reception of a synchronization signal.
In this regard, as the NR system supports multiple numerologies in a cell to support various usage scenarios, there is required the scheme for configuring the length of the cyclic prefix for a numerology different from a numerology performing the transmission of the synchronization signal.